Dynamometer for explosion-engines.



N. M. HOPKINS.

DYNAMOMETEB FOR EXPLOSION ENGINES.

APPLICATION nun) PBB.12,1D.:-"

993,990, Fatented Nov. 3, 1908.

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DYNAMOMETER FOR EXPLOSION ENGINES.

APPLICATION FILED FBB.12,1908.

Patented Nov. 3, 1908.

4mm lulu-Ill! llll NE'v'IL MONROE iiUiRlnS, OF WASHINGTON, DISTRICT OFCOLUMBIA.

DYNAMOMETER FOR EXPLOSION-ENGINES.

Specification of Letters Patent.

Patented Nov. 3, 1908.

Application filed February 12, 1908. Serial No. 415,571.

To all whom it may concern:

Be it known that l, NEVIL MONROE Hor- KISS, a citizen of the UnitedStates, residing at Washington, in the District of Columbia, ha reinvented certain new and useful Imprm'ements in Dynamometers forExplosion- Engines. of which the following is a specification.

This invention is an instrument for determining, and visually indicatingthe Working condition of explosion engines, based on the principle thatthe kinetic energy due to the explosion of a gas-mixture 1s a functionof the temperature of the gaseous reactionproducts. The instrumentcomprises a temperatlire-responsive device, preferably in theengine-cylinder and in proxlmlty to the point of gas-ignition, and anexternal indieator.

In its preferred embodiment, the instrument tundamel'itally comprises athermocouple. having its junction within the engine-cylinder and servinas the temperature-responsive device, and a mini-voltmeter, electricallyconnected to the thermo-couple and serving as the dynamometricindicator. The thermo-couple is carried by the usual sparking-plug orother sparking device used to explode the gas-mixture, thus being at thepoint of gas-ignition and maximum reaction-temperature. \Vhen theinstrument is applied to a multi-cylinder engine, a single voltmetersuflices as an indicator, having a switch for connecting the terminalsof the \'()llI1'lLtQI selectively with those of the thermo-couple in anyparticular engine-cylinder, or, in series, with the thcrmo-couples oftwo or more adjacent cylinders, so that the combined electro-motiveforce of all is indicated. \Vhen the instrument is applied to anautomobile engine, the switch may have contacts for alternativelyconnecting the voltmeter to a small dynamo, the rotor of which iscoupled or cared to a wheel of the automobile. The voltmeter is thenrovided with a second scale calibrated to in icate the speed of theautomobile in miles per hour, so that it serves both as anenergy-indicator and as a tachometer.

Referring to the accompanying drawings: Fi ure 1 is a diagrammatic sideelevation of a our-cylinder engine, each spark-plug of which hasthermo-couple terminals connected to a milli-voltmeter containing aswitch; Fig. 2 is a diagrammatic side elevation of a gasoleneautomobile, provided with the dynamometer and with a tachometer-dynamoelectrically connected to one set of terminals of the milli-voltmeterswitch; Fig. 31s a side elevation of a combined spark-plug andthermo-couple; Figs. 4 and 5 are transverse vertical sections, at aright-angle, of the combined spark-plug and thermo-couple; Fig. 6 is adiagrammatic view of the switch connections of the milli-voltmeter; andFig. 7 is a bottom end view of a plug carrying a thermo-pile only.

The explosion en ine shown in Fig. 1 comprises four cylin ers, A A A, A,respectively provided with combined sparkplugs and thermo-couples B B B,B, each of which is separately connected to the switch C of amini-voltmeter D. A tachometer-dynamo E is also connected to the switchC. i

The combined spark-plug and thermocouple illustrated in Figs. 3, 4, 5,comprises a tubular metal body 5, having a threaded end 6 which isscrewed into the explosionchamber of an engine-cylinder.

The inner end of the body carries a projecting wire loop 7, constitutingone of the sparkin electrodes. The body has three longitu inal openings8, 9, 10, which receive insulating tubes 11, 12, 13, preferably ofporcelain or lava. A filling 14 of lead is cast into the body and ontothe insulating tubes, fixing them in place and making a gastight joint.To improve the insulation, each of the tubes 11, 12, 13, preferablycontains a glass lining-tube 15, the ends of which are fused to those ofthe outer tube, to make a gastight joint.

The tube 11 contains a straight new of heavy wire 16, serving as thesecon sparking electrode. Metal caps 17 inclose the ends of the tube 11and have central openings receiving the wire 16. Nuts 18 are threaded onthe ends of the wire 16 and clamp the caps 17 onto the ends of the tube11. The upper end of the wire 16 is loosely in contact with a retainingnut 1.9, on the shank 20 of a binding-post 21 which is connected to theusual source of electric current.

The insulating tubes 12, 13, contain wires 22, 23, respectively, ofdissimilar ditlicultyfusible metals or alloys, for example one wire oflatinum and another of a platinumrho ium alloy, and the lower ends ofthese wires are fused together to provide a thermoelectric junction 24.This junction is preferably rolled thin, so as to quickly receive bear.on pairs of opposed contact-pieces, 1, 2,

, solder.

and discharge heat. The tubes l2, 13, are! of such thickness andmaterial and extend downward from the body 5 for such predetermineddistance as to permit an outflow of heat from the hot explosion-gases,through the wires 15, 16, tubes 12, 13, cast lead 14, and body-piece 5,to the engine-cylinder,just suflicient to maintain these exposed endsand the thermo-junction 24 below the ignition point of the gas-mixture.Premature firing of the gas-mixture by reason of these ex- )osedportions attaining a high temperature is thereby prevented. The upperends of the wires 22, 23 are connected to bindingposts 25, which receivewires leading to one set of contacts of the voltmeter switch C. Thisconnection is preferablv efi'ected b brass strips 26, which extend fromthe bin ing-posts and have holes into which the ends of the wires 22, 23are soldered. These holes are drilled considerably larger than the wiresand are cast full of solder. The body of solder 27 is then drilled witha small hole, through which the wire is passed and in which it is thensecured by raising the whole to the soldering-point. The wires of thethermo-cou 1e are thus mechanically out of contact wit 1 the brassterminal-strips, the electrical connection being made by the By thisconstruction changes of atmospheric temperature do not occasionvariations in the readings given by the thermocouple. Thebinding-posts25 are secured in holes in the opposite sides of a flanged porcelainsupport 28, which surrounds the upper end of the metal body-piece 5 andis secured thereto b3 a screw 29. The binding-post 21 is carrie by aporcelain cap 30, WhlCll incloses opposed projections on the upper endof the porcelaln piece 28 and is secured thereto by a screw 31.

Fig. 7 shows a plug 5 which carries a thermo-pile 24', only, instead ofa single couple. This fitting may be secured in any cylinder-openingcommunicatin directly or indirectly with the explosioniamber, ignitionof the gases being eflected by any usual means.

The switch 0 has contacts which are inclosed in the case of themilli-voltmeter D, and an external revoluble knob 32 carrying a ointer.The switch connections, shown in ig. 6, comprise separate insulatedcontactarms'33, 34, which are rigidly secured to the inner end of thknob "32. These arms are arranged to slide, respectively, onsemi-annular insulated contact-pieces 35, 36, which are connected to theends of the Winding of the mini-voltmeter D. The outer ends of the arms33, 34, are arrarsged ts excessively 3, .4, wh ch are resectively'coi'iii ected to the binding-posts of t e thermocouples- B..B?,

B, B. These four sets of bindingosts are also connected, in series, to afift set of switch contacts marked IV. The dynamomet'er scale of themilli-voltmcter has two divisions, marked respectively I and TV. Theswitch C has five external indices, 1, 2, 3, l. and IV. When the pointerof the switchknob 32 is turned toward either of the index numerals l, 2,3, 4, the thcrmo-couple of the engine cylinder A A A, or A, is put incircuit with the winding of the voltmeter. The voltmeter is so woundthat the reading thereon due to the maximum electromotive force producedin any thermo-couple by the explosion in any cylinder, under the idealconditions, is I, or thereabouts. if the pointer on the switch-knob isdirected toward either of the index numerals 1, 2, 3, or 4. and thereading on the voltmeter scale is below 1, some one of the conditions ofthe explosion is im erfect: for example the amount of combusti )levapor, or the proportion of vapor and air; the amount of com1n'ession;or the amperage or timing of the ignition-spark. The attention of theoperator is thereby at once called to the fact that the carbureter,spark-coil, or timer require adjustment; or that the cylinder, thevalves or-the pipes are leaking. If the pointer of the. switch-knob isturned toward the index numeral IV, the voltmeter then indicates thecombined voltages of the four thermo-couples and the cor respondingreading on its dial should be IV. The switch C is also provided with asixth set of terminals marked T, which are connected by leads 37,through a variable resistance R, to a tachometer dynamo E, shown in Fig.2 as driven by one wheel of an automobile. The voltmeter D is shownmounted on this vehicle to confront the operator, the COIlH(3-' tions tothe thermo-couples of four enginecylinders being also shown. When thepointer of the switch-knob 32 is turned to the index-letter T, thedynamo E is thereby coupled to the voltmeter, which has a lower scale,indicating s eed in miles per hour.

The winding 0 the voltmeter has independent binding-posts 38,which maybe used in connection with an external shunt to determine the workingcondition of the sparking batteries.

I claim:

1. In combination with an explosion-engine, a dynamometer, comprising athermocouple within the engine-cylinder, means for maintaining saidthermocouple at a temperature below the i ition-point of theexplosive-mixture, an an electric indicator connected to saidthermo-couple.

2. In combination with an explosion-engine, a-dynamometer, comprising atemperacylinder and in proximity to the gas-igniter, means formaintaining said device at a tempara-{t tre below the i nition-po'int ofthe explosive-inixture,-and -an external indicator connected to saiddevice.

tare-responsive device within the engine- 3. In combination with anexplosion-engine, a dynamometer, comprising a thermocouple within theengine cylinder and in proximity to the gas-igniter, means formaintaining said thermo-couple at a temperature below the ignition-pointof the explosive-mixture, and an electric indicator connected to saidthermo-couple.

4. In combination, an explosion-engine cylinder, a removable fittingmaking a gastight joint with said cylinder, a gas-ignite! and a temerature-responsive device, carried by said fitting, and an externalindicator connected to said temperature-responsive device.

5. In combination, an explosion-engine cylinder, a fitting making agas'tight joint with said cylinder, a gas-ignite! and a thermo-couple,carried by said fitting, and an external electric indicator connected tosaid thermo-couple.

6. In combination, a multi-cylinder explosion-engine, atemperature-responsive device Within each cylinder, an externalindicator, and means for selectively coupling the indicator to thetemperatore-responsive device of any cylinder.

7. In combination, a multi-cylinder explosion engine, ateniperature-responsive device within each cylinder, an externalindicator, and means for selectively coupling the indi cntor to thetemperatitre-responsive device of any cylinder or to the devices of agroup of adjacent cylinders.

8. In combination, a multi-cylinder explosion-engiue, a thermo-couplewithin each cylinder, an external electric indicator, and a switch forselectively coupling the indicator to the thermocouple of any cylinderor to the thermocouples of a group of adjacent cylinders.

9. In combination, a multi-cylinder explosion engine. a thermo couplewithin each cylinder, an external electric indicator, and a switch forselectively coupling the indicator to the thermo-couple of any cylinderor in series to the thermo-couples of a group of adjacent cylinders.

10. In combination with a conveyance and an explosion-engine for drivingsaid conveyance, a thermo-couple in position to receive heat from theexplosion-gases, a dynamo driven by the movement of said conveyance, anelectric indicator having a dynamometer scale and a tachometer scale,and

a switch for coupling the indicator either to the thermo-couple or tothe dynamo.

11. In combination, a fitting adapted to make a as-tight joint with anexplosion-engine cy inder, a thermo-couple carried by said fitting, andmeans for maintaining said thermo-couple at a temperature below theignition-point of the explosive-mixture.

12. In combination, a fitting adapted to make a gas-tight joint with anexplosion-engine cylinder, and a gas-igniter and atemperature-responsive device carried, in proximity, by said fitting.

13. In combination, a fitting adapted to make a gas-tight joint with anexplosion-engine cylinder, and a gas-igniter and a thermo-couplecarried, in proximity, by said fitting.

14. In combination, a su port having three openings, insulating tu esextending through said openings, a" metallic filling cast into saidsupport and onto said tubes, a thermo-couple having leads extendingthrough two of said tubes, and a sparkingelectrode having a leadextending through the third tube.

15. In combination, a support, insulating tubes carried by said support,and a thermocouple, comprising wires extending through said tubes andhaving a fused junction flattened into a thin broad piece.

In testimony whereof, I atiix my signature in presence of two Witnesses.

N EVIL MONROE HOPKINS. Witnesses EUGENE A. BYRNEs, C. W. FOWLER.

